FIG. 10 is a perspective view illustrating a prior-art wire bonding device.
In this wire bonding device, XYZ axes form a three-layer structure On a first layer 2, a fixed base 3 is arranged, and an X-axis cross roller guide 4 is provided on the fixed base 3. On a X-axis motor portion 15, an X-linear motor 17 is arranged. By means of the X-linear motor 17, a lower moving plate 6 is moved in an X-axis direction on the X-axis cross roller guide 4. On a second layer, a Y-axis cross roller guide 12 is arranged, and by means of a Y-linear motor 42, an upper moving body 10 is moved in a Y-axis direction on the Y-axis cross roller guide 12.
On a third layer, a Z-rotation fulcrum placed on the upper moving body 10 is provided, and at this Z-rotation fulcrum, an ultrasonic horn and a capillary are arranged so that the Z rotation fulcrum is swung/driven by a Z-motor (not shown). That is, it is so constituted that by means of a driving force of the Z-motor, the capillary and the ultrasonic horn can be moved in a Z-axis direction Moreover this device has a bonding mechanism (not shown) for performing bonding by supplying a wire to the capillary.
The aforementioned bonding mechanism is a mechanism in which the wire is supplied to the capillary, a ball is formed at a tip end of the wire fed out of the capillary, the ball is moved by the capillary to a 1st bonding point, and at that time, by applying a pressure to the ball from the capillary while applying the ultrasonic vibration to the ball by the ultrasonic horn, the wirebonded to the 1st bonding point and then, the capillary is moved to a 2nd bonding point and at that time, by applying the pressure from the capillary while applying the ultrasonic vibration to the by the ultrasonic horn, the wire is bonded to the 2nd bonding point.
In the aforementioned wire bonding device, by moving the lower moving plate 6 in the X-axis direction by the X-linear motor 17 of the first layer 2, the upper moving body 10 placed on that, and the ultrasonic horn and the capillary at the Z-rotation fulcrum are also moved in the X-axis direction. Moreover by moving the upper moving body 10 in the Y-axis direction by the Y-linear motor 42 of the second layer, the ultrasonic horn and the capillary placed on that at the rotation fulcrum are also moved in the Y-axis direction. However even by moving the upper moving body 10 in the Y-axis direction, the lower moving plate 6 is not moved. Moreover, the capillary and the ultrasonic horn at the Z-rotation fulcrum are swung by the Z-motor of the third layer However, even if the Z-rotation fulcrum is swung, the lower moving plate 6 and the upper moving body 10 are not moved except a swing Y-component of the Z-axis. As the result of synthetic driving from the first layer to the third layer, precise XYZ movement is realized.
Since the Z-motor of the third layer is exclusively for swing of the Z-rotation fulcrum, it cannot contribute to driving of the X-linear motor 17 of the first layer in the X-axis direction at all but becomes a genuine Similarly, since the Y-linear motor 42 of the second layer is exclusively for movement of the upper moving body 10 in the Y-axis direction, it becomes a load on driving of the X-linear motor 17 of the first layer in the X-axis direction. Moreover, since the Y-axis cross roller guide 12 is arranged on the X-axis cross roller guide 4 and Z-motor is mounted in a box-shaped housing, a, certain degree of size is needed and they also become loads. Therefore, the X-linear motor 17 has a relatively larger load than the Z-motor and is disadvantageous in high acceleration/deceleration.
When the ultrasonic horn and the capillary at the Z-rotation fulcrum are accelerated/rotated, a reaction force is generated fixed portion of the Z-motor, and its vector has an angle close to a right angle with respect to each of the X-axis and the Y-axis and thus, the generated reaction, for becomes a vibration source.